1. Technical Field
The application generally relates to a tool coupler for connecting tool heads, such as drills, reamers, millers, turn-cutters, dies, and rams, to a tool holder. The application further relates to a tool coupler for connecting a replaceable tool head to a machine tool comprising an at least partly or fully conical or cylindrical hollow shaft and a ring-shaped collar interacting with a correspondingly configured receiving bore hole and a ring-shaped opposite surface of a basic holder on a machine tool, where the basic holder and the tool coupler can be locked by means of clamping elements actuated via a clamping device in such a way that the collar of the tool coupler abuts on the opposite surface of the basic holder, and the tool coupler is provided with a continuous gripper groove for a gripping device used in automatic tool replacement.
2. Background Information
Couplers of this type are known, for example, from EP 0 343 190 B1 where the latter coupler works with balls as clamping elements, which are driven via a tension rod radially outward when the tool is mounted and radially inward when the tool is removed into existing openings. Another comparable tool coupler with wedge-shaped clamping elements is shown and described in DE 38 07 140 C2. The combination of a hollow cone shaft, which, compared to the respective receiving bore hole, is slightly overdimensioned in the range of elastic deformation, with the mutual flat abutment achieves high axial rigidity under static and dynamic load forming a tool coupler for connecting a tool holder and a basic holder, possibly in the form of a machine tool spindle seat, which is useable in tool machines for turning, drilling and milling. As a result, the machine tool can be used as a machining center for many different cutting operations. In fully automated production, the so-called tool replacement systems are becoming increasingly important where, instead of manually replacing the tool, a gripper groove is provided an the tool head or on the tool coupler for replacing the tool head.
However, in order to precisely adjust the tool head and the tool coupler, which may also be a separate intermediate piece for seating and mounting a tool head, in a machine tool spindle or a basic holder on the one hand and a tool magazine, such as a revolving disk, on the other hand, with regard to the angle of rotation, further positioning elements are required. According to prior art, catches or other switching areas and locating faces disposed on the outside surface of the tool coupler are used in connection with positioning elements, such as pins in the basic holder or a machine spindle. In order to orient the tool coupler in the magazine on the one hand and in the tool coupler seat on the other hand and for preventing 180° misalignments, such switching areas and locating faces are provided on diametrically opposite surface areas of the tool coupler.
For the tool carrier according to EP 1 007 256 B1, diametrically opposite recesses are used, which have to be configured with varying geometry for the above mentioned reasons. The unbalance resulting from the configuration manifests itself especially in tools rotating at high speed. In order to compensate the source of unbalance and other unbalances resulting from asymmetrical tool coupler configurations, it is proposed for the tool carrier according to EP 1 007 256 B1 to provide one or more bore holes on the inside of the tool carrier. However, the tool carrier of EF 1 007 256 B1 is disadvantageous in that it matches only one certain machine tool type.